Fluorescence Detection by Intensity Changes (FDIC), a useful analytical tool for complex mixtures based on non-covalent interactions
Researcher:
Jarne Lardiés, Carmen
Congress:
1st International Caparica Conference on Chromagenic and Emissive Materials, IC3EM 2014
Participation type:
Comunicación oral
Year:
2014
Location:
Costa de Caparica (Portugal)
Certain fluorophores experience significant changes, either increases or quenching, in the presence of a wide number of molecules, including non-fluorescent or chromophore-free ones. This occurs without changes in their emission wavelength [1]. The generated fluorescence is due to non-specific, induced electrostatic interactions between the charge or permanent dipole moment of the fluorophore and the long polarizable hydrocarbon chain of analytes [2]. Although this phenomenon also takes place in solution, it is significantly sensitive on silica gel layers due to the additional effect of refractive index on the radiative constant, after analyte addition [3].
Therefore, fluorophores, impregnated on silica gel HPTLC plates, have proved useful for a sensitive, quantitative detection of a variety of analytes having poor absorption properties in different matrices, after chromatographic separation. This has been referred to as fluorescence detection by intensity changes (FDIC) [2,4]. The magnitude of emission can be modulated through chromatographic parameters and fluorophore concentration, and used for quantitative purposes.
Mechanisms are discussed here and several examples will be presented in this meeting. Thus, berberine cation is useful to determine saturated hydrocarbons in petroleum-related products [5], as well as neutral lipids in mixtures [4]. Coralyne cation behaves as a probe for alkanes [6], surfactants, lipids and self-organized molecular aggregates. Likewise, primuline plays a double role in an original hyphenated analytical system designed for lipid analysis: it allows separated lipids to be quantified by FDIC; and it is compatible with an API-Mass Spectrometry analysis of these compounds, allowing a direct transfer of separated peaks to be carried out.
Selection from a number of fluorophores offers analysts the flexibility to develop their own procedures, with the additional advantage that this technique is not destructive, as only non-covalent interactions are involved.
Certain fluorophores experience significant changes, either increases or quenching, in the presence of a wide number of molecules, including non-fluorescent or chromophore-free ones. This occurs without changes in their emission wavelength [1]. The generated fluorescence is due to non-specific, induced electrostatic interactions between the charge or permanent dipole moment of the fluorophore and the long polarizable hydrocarbon chain of analytes [2]. Although this phenomenon also takes place in solution, it is significantly sensitive on silica gel layers due to the additional effect of refractive index on the radiative constant, after analyte addition [3].
Therefore, fluorophores, impregnated on silica gel HPTLC plates, have proved useful for a sensitive, quantitative detection of a variety of analytes having poor absorption properties in different matrices, after chromatographic separation. This has been referred to as fluorescence detection by intensity changes (FDIC) [2,4]. The magnitude of emission can be modulated through chromatographic parameters and fluorophore concentration, and used for quantitative purposes.
Mechanisms are discussed here and several examples will be presented in this meeting. Thus, berberine cation is useful to determine saturated hydrocarbons in petroleum-related products [5], as well as neutral lipids in mixtures [4]. Coralyne cation behaves as a probe for alkanes [6], surfactants, lipids and self-organized molecular aggregates. Likewise, primuline plays a double role in an original hyphenated analytical system designed for lipid analysis: it allows separated lipids to be quantified by FDIC; and it is compatible with an API-Mass Spectrometry analysis of these compounds, allowing a direct transfer of separated peaks to be carried out.
Selection from a number of fluorophores offers analysts the flexibility to develop their own procedures, with the additional advantage that this technique is not destructive, as only non-covalent interactions are involved.